Method for prevention of seepage of water



Patented May 23, 1939 PATENT OFFICE f METHOD FOR PREVVVEANTION OF SEEPAGE OF TER,

pen F. Powell, Custer, s. ma, dedicated to the free use of the People of the United States No Drawing. Application April 13, 1937,

Serial No. 136,614

1 Claim.

(Granted under the act oi. March 3, 1883, as

. amended April 30, 1928; 370 0. G. 757) This application is made under the act oi March 3, 1883, as amended by the act of April 30, 1928, and the invention herein described and claimed, if patented, may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

I hereby dedicate the invention herein described to the free use of the People or the United States to take effect on the granting of a patent to me.

My invention relates to the use of bentonite to impede and control the flow of water in underground channels and pervious strata, through dams, road and highway fills, and other earthen embankments. I

Bentonite is the geological and trade name of a natural hydrous silicate of alumina, containing also varying but small amounts of iron, lime, or

magnesia silicates or alkalies. In the presence of water in sufiicient quantity, bentonite has the distinctive property of forming a. highly viscous solution or gel, which expands to many times the volume of the dry bentonite.

I have found that a freshly mixed bentonite, as more fully illustrated by the hereinafter examples, when properly injected into masses of porous or seamy materials such as sand,

- gravel, or rock, penetrates'the minute voids, and

coats the small and large particles with a gel which tends to prevent the passage of percolating water;

1. The object of my invention is the Prevention of water seepage through the body of pervious earthen dams.

2. Another object of my-invention is the prevention of water seepage under dams.

3. Another object of my invention is the preinvention when directed to prevent seepage of water through the body of pervious earthen dams, I submit the following:

Example 1.Bentonite in proportions varying solution of.

from 5 to by weight is added to water and thoroughly mixed by agitation and stirring. The 5% solution is used for treatment of fine sand and for rock which contains very fine seams. For coarser sand and gravel and for rock with larger seams, an 8 to 12% solution is used. For

large seams, fissures, and caverns, the 15% solu-r tion will be most effective, The addition of clay, I fine sand, or other granular and inert material in varying proportions up to by weight has been found advantageous for the sealing of large fissures and caverns, due to the increased frictional resistance which the mixture oifers against removal under subsequent water pressure.

, Preparation of a pervious dam for the introduction of bentonite solution'consists in drilling or boring holes of proper various depths and at optimum spacing. In general the holes are so spaced in the faulty spots of the impervious section of the dam or sections to be rendered impervious, so these will become completely impregnated.

The bentonite solution is introduced into the fill by means of pipe of substantially one-half to three inches in diameter inserted to the required depth into the holes described above. The pipe is packed or cemented into the holes a sufiicient sure of to 120 pounds per square inch applied either by pumping or by compressed air introduced on top of a cylinder containing the solution.

In carrying out my invention when directed to the use of bentonite to prevent the seepage of water under dams, I submit the following:

Example 2.--To prevent the seepage of water through the foundations of dams, holes are drilled to the required depth in the foundation (depending on the depth of porosity) at intervals to give a continuous impregnation along or parallel to the axis of the dam.

In these holes are inserted pipes for connection to the pressure apparatus and bentonite mixtures are introduced as described in Example 1 above.

In carrying out my invention when directed to the use of bentonite to prevent the seepage of water around dams, I submit the following:

' Example 3.--Holes of the required depth and spacing are drilled, generally normal to the thalweg of the valley in which the dam is located and on an extension. of the axis of the dam. In fractured rock these holes are so placed in depth and location, where possible, to intersect all cracks duced as described in Example 1 above, usually to complete resistance.

In carrying out my invention when directed to the use of bentonite to make impervious porous soils surrounding wet excavations, I submit the following:

Example 4.The excavation is surrounded by a system of holes, drilled from the surface to impervious underlying strata. These holes are usually at a distance from the edged the proposed excavation not less than the depth of the pervious strata to be treated.

The holes are so spaced that the bentonite, when forced into the interstices of the gravel, rock or porous soil, will completely fill an area surrounding the excavation and will cut off or reduce the amount of flow into the excavation.

Preparation and application of the bentonite solution is the same as described in Example 1.

In carrying out my invention when directed to the use of bentonite for filling sub-surface channels in order to raise sub-surface stream flows to the stream channel, I submit the following:

Example 5.--On a line normal'to the stream channel and at optimum intervals, holes are drilled to the impervious strata underlying the aggraded water bearing deposit in the valley of the stream.

Into these holes are introduced pipes to each of which is attached the connection from the apparatus supplying the bentonite solution under "pressure. A sub-surface dyke or cofler dam is thus introduced in the water bearing deposit which causes the water to rise to the surface and flow in the stream channel.

Preparation and application of the bentonite solution is the same as described in Example 1. In carrying out my invention when directed to the use of bentonite to impede the flow of water in seeps and through road and highway fills, I submit the following:

Example 6.-The methods employed here are the same as described under Examples 1 and 2, above. The bentonite is introduced into either the highway fill or road or in adjacent or underlying soil.

While I have described my invention in detail, it is to be understood that I do not restrict myself to the proportions given or the uses to which my invention may be put. The aforementioned ex- .amples are suggested by way of illustration only. 

